Referring to FIG. 1, a conventional respiratory mask 11 includes a mask unit 111 adapted to cover the mouth and nose of a user 12 and a rigid forehead supporting member 112 mounted to the mask unit 111 and adapted to abut against the forehead of the user 12. The mask unit 111 is adapted to be provided with a gas tube 13 for supplying the user 12 with positive pressure air therethrough.
When in use, two straps 14 are respectively connected to the forehead supporting member 112 and the mask unit 111. Each of the straps 14 extends from two opposite ends of a corresponding one of the forehead supporting member 112 and the mask unit 111 for surrounding the user's head. Thereby, the two opposite ends of the forehead supporting member 112 abut against the forehead of the user 12 and the two opposite ends of the mask unit 111 abut against the cheeks of the user 12 for covering his/her nose and mouth. However, the fittingness and closeness of the respiratory mask 11 on the user 12 depend largely upon the facial features of the user 12, such as face, forehead and nose shapes. In other words, the conventional respiratory mask 11 is unable to fit closely onto all faces and may result in the user's uncomfortableness or air leakage.